The invention relates generally to scribing a semiconductor substrate and more particularly to methods and apparatus for scribing a semiconductor substrate using a laser.
A method of scribing a substantially planar substrate comprising semiconductor material along at least one scribeline by way of relative motion of the substrate with respect to a laser beam, whereby localized energy is transferred from the laser beam to the substrate along the course of said scribeline is set forth, for example, in WO 2002/076699 A1. Here, a single laser beam is used to create ablated tracts along scribelines arranged in an orthogonal grid structure on a major surface of a coated semiconductor wafer. Once this network has been created, a mechanical saw is used to singulate the substrate into dies by cutting along said tracts.
Another method of this type is set forth, for example, in International Patent Application WO 1997/029509 A1. In this document, a linear cluster of laser beams is used to ablate substrate material along a scribeline, thus causing the substrate to be “radiatively scored” along the line of ablation. The use of multiple beams in this manner as opposed to a single (more powerful) beam can help to produce a narrower ablation tract on the substrate. This can have certain advantages, particularly when the scribeline in question is in close proximity to (fragile and expensive) devices on a semiconductor substrate, for example.
In the Figures, corresponding parts are indicated using corresponding reference symbols.